Silence more static analyzer warnings.

Add in definedness checks for shift operators, null checks when
pointers are assumed by the code to be non-null, and explicit
unreachables.

llvm-svn: 224255

3 files changed, 7 insertions, 2 deletions

diff --git a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64AddressingModes.h b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64AddressingModes.h
index 0c0801d5232..ef5bb716017 100644
--- a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64AddressingModes.h
+++ b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64AddressingModes.h
@@ -236,6 +236,7 @@ static inline bool processLogicalImmediate(uint64_t Imm, unsigned RegSize,
 
   if (isShiftedMask_64(Imm)) {
     I = countTrailingZeros(Imm);
+    assert(I < 64 && "undefined behavior");
     CTO = CountTrailingOnes_64(Imm >> I);
   } else {
     Imm |= ~Mask;
diff --git a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp
index 60e9c19dbc0..8dc6c305b98 100644
--- a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp
+++ b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp
@@ -177,7 +177,9 @@ private:
     MCELF::SetType(SD, ELF::STT_NOTYPE);
     MCELF::SetBinding(SD, ELF::STB_LOCAL);
     SD.setExternal(false);
-    Symbol->setSection(*getCurrentSection().first);
+    auto Sec = getCurrentSection().first;
+    assert(Sec && "need a section");
+    Symbol->setSection(*Sec);
 
     const MCExpr *Value = MCSymbolRefExpr::Create(Start, getContext());
     Symbol->setVariableValue(Value);
diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index 8208c125374..3fce38e2e3d 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -8577,7 +8577,9 @@ static SDValue PerformBFICombine(SDNode *N,
     unsigned InvMask = cast<ConstantSDNode>(N->getOperand(2))->getZExtValue();
     unsigned LSB = countTrailingZeros(~InvMask);
     unsigned Width = (32 - countLeadingZeros(~InvMask)) - LSB;
-    unsigned Mask = (1 << Width)-1;
+    assert(Width < std::numeric_limits<unsigned>::digits &&
+           "undefined behavior");
+    unsigned Mask = (1u << Width) - 1;
     unsigned Mask2 = N11C->getZExtValue();
     if ((Mask & (~Mask2)) == 0)
       return DCI.DAG.getNode(ARMISD::BFI, SDLoc(N), N->getValueType(0),